Rust preventive lubricating oil compositions



Patented Jan. 13, 1948 RUST PREVENTIVE LUBRICATING OIL COMPOSITIONSGordon W. Duncan,

Westfield, N. J., assignor to Standard Oil Development Company, acorporation of Delaware No Drawing. Application December 30, 1944,Serial No. 570,787

4 Claims. (Cl. 252-56) This invention relates to slushing compositions,that is, to non-drying compositions of matter for arresting, preventingand inhibiting the corrosion of metals.

The corrosion of a sult'of chemical reactions between the environof themetal. By coating metallic surfaces with an inert, impervious film, bydipping, spraying, brushing, or swabbing, the development of theseelectrochemical relations can be impeded and arrested and thus activecorrosion prevented. The use of a slushing formation of a relativelythick, viscous liquid or semi-solid layer which is easily removable fromthe surfaces over which it is spread by Wiping with a cloth or flushingwith a readily available solvent. More durable application to facilitatetreatment of the metal surface. In no case, however, is the protectivelayer of the nature of a diflicultly-removable varnish-like layer. Theuse of slushing compositions is particularly advantageous when metallicas engine parts during storage or tubing during shipment, yet must befreed of any coating before use.

ing on the film. In order to overcome this difficulty and to increasethe effectiveness of the coating film, it has been suggested thatmaterials in the nature of soaps be included in the hydrocarboncomposition. Even though these soaps arises through the fact that theyare ash-forming materials. It is often desirable to protect an internalcombustion engine both internally and externally for storage purposes.When such engines are removed from storage the proper care is not takento completely remove the protective coating; Thus, when the engine isput into service the protective coating is burned off, leaving anabrasive ash, which, by

increasing combustion chamber deposits, shortens the time intervalbefore engine overhaul is required.- The presence of this ash promoteswear in the internal parts of the engine. Another objection to the soaptype rust preventive agents is their relative ineffectiveness in certainbase stocks, particularly high viscosity, highly-refined lubricatingoils.

An object of the present invention is the formation of non-dryingcomposition of matter for arresting, preventing, and inhibiting thecorrosion of metals. This and other objects will be apparent to thoseskilled in the art upon reading the following description.

It has now been found that when small amounts of carboxylic acid estersof partially dehydrated polyhydric alcohols are incorporated in slushingcompositions the composite is characterized by marked anti-corrosiveproperties and contains no ash-forming constituents. The compositions ofthe invention are therefore improved slushing oil compositions whichcontain, in addition to the above described esters, the usualconstituents of a protective base material which is generally a mineraloil product such as a light mineral oil distillate, a mineral oil ofabout lubricating consistency, or a more resistant non-drying coatingmaterial such as petrolatum or any of the various petroleum waxes. Alsowaxes and oils of animal, including degras, lanolin, or vegetable originmay be used as the base material if desired. In many instances the rustpreventive compositions may be diluted with a volatile solvent tofacilitate application.

The anti-corrosion agents contemplated according to the presentinvention are carboxylic acid esters of partially dehydrated aliphaticpolyhydric alcohols such as the hexitols. Partial dehydration convertsthe polyhydric alcohol to an epoxide or inner ether type of compoundhaving hydroxyl substituents and either one or two mono-oxy, 4-7membered carbon-oxygen rings in its probable chemical figuration. Thehydroxyl groups attached to the inner ethers still retain the typicalreaction of an alcohol,

a fatty acid to produce an ester. The esterification of one or morehydroxyl groups in the partially dehydrated polyhydric alcohol yieldsesters found to be useful for the purposes of the present invention. Theacids useful for the esterification of the cyclic ether-alcoholcompounds, are those fatty acids having 8 to 30 carbon atoms permolecule such as those which are present combined with glycerine innatural occurring animal and vegetable oils and fats and which arederived therefrom upon saponification thereof and are exemplified by thefatty acids derived from stearin, whale oil, menhaden oil, neats foot011, castor oil, corn oil, cottonseed oil, coconut oil, linseed oil,palm kernel oil, rapeseed oil, China-wood oil, perilla oil, soya beanoil, sunflower oil, olive oil and the like and includes fatty acids suchas caproic, capryllic, capric, lauric, myristic, palmitic, oleic,linoleic, linolenic, rlcinoleic, stearic. dihydroxy stearlc,oleostearic, erucic, and behenic. Also fatty acids such as syntheticallyprepared aliphatic monocarboxylic fatty acids as for instance margaricor fatty acids prepared by suitably oxidizing hydrocarbons or byhydrogenating naturally occurring fatty acids may be used. Thenaphthenic acids recovered from certain petroleums are also eminentlysatisfactory. It is also contemplated that mixtures of the foregoingacids may be used in the esterification of the partially dehydratedpolyhydrlc alcohols. An example of a partially dehydrated polyhydrlcalcohol is a partially dehydrated sorbitol commonly known I as sorbitan.

The anti-corrosion agents of the present invention are made by reacting1 mol of the polyhydric alcohol or 1 mol of the partially dehydratedalcohol with one to three mols of carboxyllc acid or carboxylic acidmixtures either in the presence of or absence of a catalyst. Thecatalyst may be acidic, for example, sulfuric or phosphoric acid oralkaline, like sodium hydroxide. The ingredients are commingled andheated in a kettle or other container preferably closed and equippedwith suitable agitating means at a temperature of l50-300 C. until thereaction reaches the desired stage. It is frequently desirable tomaintain an atmosphere of inert gas such as nitrogen or carbon oxideover the reacting mass as by passing an inert gas over or through thereacting mass in order to assist removal of the water of condensationand prevent discoloration of the esters formed or the reaction may becarried out in a refluxing hydrocarbon solvent, with means provided fortrapping out the water formed. The esters useful as anticorrosionaddition agents according to the present invention are known to the art,methods for their preparation having been described by K. R. Brown in U.S. Patent 2,322,820. Examples of such esters are the mono esters such assorbitan mono-oleate, sorbitan mono-laurate, and the like which may alsobe referred to as mono-oleylepoxy sorbitolate or the correspondinglauryl compound, etc., as mentioned more specifically hereinafter.

The compositions of the present invention as before stated comprise anoleaginous base blended with a minor proportion of a carboxylic acidester of partially dehydrated aliphatic straight chain polyhydricalcohols. Specific examples of the polyhydrlc alcohols which may bepartially dehydrated and then esterified or converted to esterscontaining an reaction are mannitol, sorbitol and dulcitol. A specificexample of an ester would be mono-oleylepoxymannitolate. The slushingcompositions are produced by blending from .5% to 10% or lesser amounts,say from .1 to 5% of the ester in the oleaginous base using heat andstirring if necessary.

In many cases it is desirable iary agents These include carboxylatesoaps, sulfonate' soaps, such as calcium soap of mahogany sulfonates,phenolates, phenol sulfides, wool grease, or-

to include auxil- 4 garlic bases. etc. For special purposes, such as toenable the composition to dislodge water from metal surfaces, alkylolamines, alcohols. esters, ethers, ether alcohols, and the like may beincorporated in the composition. In still other instances anti-oxidants,such as amine or phenols, thickeners, such as polybutene, acryloid,copolymers of styrene and olefins or diolefins, ester polymers,metal-deactivators, dyes, olliness agents, extreme pressure additives,and greaseforming soaps are desirable.

The efficiency of coating composition is evaluated by certain standardtests of which the humidifier is the more important.

Test procedure Sand blasted panels of hot rolled steel are dipped intoslushing compound samples, then maintained vertically in a box for 16hours under ordinary room conditions to allow the rust preventive filmto reach an equilibrium condition. Compounds containing petrolatum orwaxes are applied at temperatures above their melting point and fluidproducts are applied at room temperatures. The coated panels are thenplaced and spaced apart in an upright position in a humidifler chamberwherein at 100 F. they are subjected to continuous moisturecondensation. The time, in hours, for a panel subjected to theseconditions to develop initial evidence of rusting is observed andrecorded as the resistance life of the coating composition.

The following data illustrate the rust preventive effectiveness of thepresent invention:

Blend Time Lubricating oil (100 Vis. at 100 F.) 1 hour. Lubricatingoil+2.5% mono lauryl- 196 hours.

e xy sorbitolafe.

Lu rlcating 0' +5% mono lauryl-epoxy 200+ hours.

sorbitolafe.

Lubricating oil+2.5% mono eloyl- 196 hours.

epoxy sorhitola'e.

Lubricating oii+5% mono cleyl-epoxy 200+ hours.

sorbitolate.

Petrolatum Severe rust at 168 hour s.

Petrolatum-H% mono lauryl epoxy 500+ hours.

sorbitolate.

Aviation engine oil 1 hour.

Aviation engine oil+3% mono eloate 200+ hours.

of mono dehydrated sorbitol.

Aviation engine oil+2% mono oleate 200+ hours.

of mono dehydrated sorbitol+l% calcium sulronate.

100 F. Flash solvent naphtha+l0% 200+ hours.

wool grease, 8% naphthenic residual oil, 2% mono oleate of monodehydrated sorbitol.

What is claimed is:

inner ether linkage by one in the rust preventive composition.

1. A slushing composition consisting essentially of a material selectedfrom the class which consists of petroleum lubricating oils andpetrolatum and 0.5 to 10% by weight of a fatty acid monoester ofsorbitan, the fatty acid radical of said ester having between 8 and 30carbon atoms. the quantity of said ester being sufficient to impart rustpreventing properties to said petroleum composition.

2. A rust preventive, composition consisting essentially of alubricating oil having a viscosity of about S. S. U. at 100 F. and from2.5 to 5% of sorbitan mono-laureate.

3. A rust preventive composition consisting essentially of a lubricatingoil having a viscosity of about 100 S. S. U. at 100 F. and from 2.5 to5% of sorbitan mono-oleate.

4. A rust preventive composition consisting es- 5 sentially orpetrolatum containing about 1% of Number sorbltan mono-laureate.2,285,422 GORDON W. DUNCAN. 2,294,140 2,322,820 REFERENCES CITED2,322,821 The following references are of record in the 2322-322 file ofthis patent: NITED STATES PATENTS 1 981193 Number Name Date 10 2,404,2407 1,630,101 ,Wilkin May 24, 1927 6 Name Date .Epsteln June 9, 1942Taylor Aug. 25, 1942 Brown June 29, 1943 Brown June 29, 1943 Brown June29, 1943 Barnett Nov. 16, 1943 Brown Apr. 3, 1945 Sharp Apr. 9. 1946MacLaurin July 16, 1946

